State Sen. Sally Fox, D-Chittenden, listens during debate on the Senate floor in April 2012 in Montpelier.

MONTPELIER — Chittenden County Sen. Sally Fox died early Friday after a prolonged battle with lung cancer.

Fox, 62, a Democrat from South Burlington, was diagnosed with sarcoma in 2012. The longtime lawmaker was elected to the Senate in 2010 after a lengthy earlier stint in the House. She was currently serving on the Senate Health and Welfare and Appropriations committees.

House Speaker Shap Smith announced her death Friday morning in the House chamber, saying she had died peacefully, surrounded by family, around 3:15 a.m. Many lawmakers gasped upon hearing the news, and some were emotional.

Later in the morning, Lt. Gov. Phil Scott gaveled the Senate to order “with a heavy heart,” noting that Fox’s death was “bringing the first week of the session to a tragic close.” Fox’s seat sat empty, and her desk was clear except for a single white rose.

Senate President Pro Tem John Campbell said on the Senate floor that the news of Fox’s death made it “very difficult to compose our thoughts.” He said a resolution honoring her will be prepared for Tuesday, when senators will be able to provide their own remarks in her honor.

In a statement, Campbell praised Fox as a tireless advocate who always looked out for vulnerable Vermonters. He said that “her spirit will live on and provide us with guidance, compassion and support.”

“It would be difficult to find a more passionate advocate and champion for our most vulnerable citizens — the young, the elderly and the disabled,” Campbell said. “As a Chittenden County state senator, she fought tirelessly to ensure that all Vermonters have access to quality health care, that those who suffered from mental illness are not forgotten, and that our children are provided with every opportunity to succeed.”

Both Campbell and Smith noted Fox’s absence Tuesday when the Legislature reconvened for the 2014 session. Moments of silence were held in her honor in both the House and Senate.

Many of Fox’s colleagues in the Legislature echoed Campbell’s sentiments Friday, noting that she was deeply respected for her work advocating for the poor and disabled through her work as an attorney with Vermont Legal Aid.

Fox was elected to the House in 1986 and served in that chamber for 14 years. In the House she served as chairwoman of the Appropriation and Judiciary committees and as assistant majority leader.

According to her Senate campaign website, Fox was most proud of her role in creating the Vermont Family Court system, which consolidated all family- and child-related issues into a single venue.

Sen. Claire Ayer, chairwoman of the Senate Health and Welfare Committee, said on the Senate floor that a table was placed outside the committee room to allow people to leave messages for Fox’s family.

“A lot of people who work in this building — lobbyists, students, pages, whatever — are grieving about Sen. Fox, and … it’s surprising the number of constituents who come here … who are grieving and would like to say something to her family, so we have put some paper out there and a pen,” she said.

By Friday afternoon, dozens of messages had already been left.

Gov. Peter Shumlin, who served on the Judiciary Committee when he was appointed to the House, said Fox was a mentor to him and will be remembered for her role as an advocate.

“Sally Fox was a relentless champion for kids and vulnerable Vermonters. Those who often lack a voice always had an advocate with Sally in the State House,” Shumlin said in a statement. “Sally took me under her wing and taught me a great deal about how to effectively serve Vermonters in the State House. She was a great friend, and I will miss her tremendously.”

Shumlin on Friday ordered all flags at the State House, federal and state facilities and public buildings and grounds around the state to be flown at half staff from sunrise Sunday until sunset Tuesday.

The governor has the task of appointing a senator to serve until the next election.

Fox is survived by her husband and two adult sons.

Services will take place at 1 p.m. Sunday at Temple Sinai in South Burlington, followed by a private burial.